We derive a formula for correcting the weight of food eaten by an animal for natural weight loss (or gain) of the food, such as through moisture loss and food respiration. The formula is derived using a differential equation to model the loss in fresh weight based on a constant consumption rate and assumptions about the form of the function for weight loss over time of the aliquot. The standard formula is shown to over-estimate the weight of eaten food compared to our theoretically derived formula. This over-estimation is negligible (< 0.2%) for moisture loss below about 10% but increases sharply to 8% when moisture loss is 50%. We illustrate the application of these two formulae using a laboratory study of consumption rate by larvae of a phytophagous insect: the Tasmanian eucalyptus leaf beetle, Chrysophtharta bimaculata (Olivier) (Coleoptera: Chrysomelidae).
History
Publication title
Australian Journal of Entomology
Volume
41
Issue
2
Article number
2
Number
2
Pagination
170-173
Department/School
Biological Sciences
Publisher
Blackwell Publishing Asia
Publication status
Published
Rights statement
The definitive published version is available online at: http://onlinelibrary.wiley.com/